Cystopteris japonica Luerssen in Engler, Bot. Jahrb. Syst. 4: 363. 1883.

Plants summer-green. Rhizome creeping, 2-4 mm in diam., with sparse yellowish brown, broadly lanceolate, thinly membranous scales. Fronds approximate; fertile frond (12-) 40-60(-90) cm; stipe chestnut-black or purple-brown, (6-) 15-25(-40) cm, (1-)2-3(-4) mm in diam., grooved adaxially, with sparse scales at base, upward glabrate, shiny; lamina 2- or 3-pinnate, broadly ovate to deltoid-ovate, (6-)20-35(-50) × (3.5-)15-18(-40) cm, not narrowed to base, herbaceous, base subcordate, apex shortly acuminate or acuminate; pinnae 10-15 pairs, opposite or subopposite, 3-4 cm apart, spreading or ascending, subsessile or very shortly stalked, basal pair not shorter, oblong or broadly lanceolate; upper pinnae lanceolate, (1.8-)8-15(-25) × (1-)3-6(-11) cm, base subtruncate, apex acuminate; pinnules 10-24 pairs, sessile, alternate, subequilateral, basiscopic pinnules slightly longer than acroscopic pinnules; basal pair slightly shorter, subopposite or anadromous, oblong, (0.5-)2.5-4(-6) × (3-)6-10(-20) mm, base truncate or broadly cuneate, apex obtuse; costae chestnut-brown or stramineous in distal half; pinnule segments 5-14 pairs, spreading or slightly ascending, oblong, crenate, apex obtuse; veins pinnate in segment, simple, reaching marginal teeth. Hyaline multicellular long hairs and scalelike hairs sparse on both sides of veins, costae, rachis, and stipe. Sori orbicular, abaxial on basal acroscopic veins; indusia pale green, broadly ovate, small, membranous, glandular, sparsely ciliate at margin, proximal to sorophore, hidden by sporangia at maturity, persistent. Spores yellow, bean-shaped or long spheroidal, perispore with dense inflated, bulbous processes. 2n = 84*, 168*.

Forests in valleys; 400-2800 m. Chongqing, Fujian, Guangxi, Guizhou, Hubei, Hunan, Jiangxi, Yunnan, Zhejiang [Japan].